Balloon catheter with improved pushability

• US 8,172,864 B2
• Filed: 12/15/2009
• Issued: 05/08/2012
• Est. Priority Date: 05/12/2003
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Wu, Show-Mean
• Primary Examiner(s): NGUYEN, TUAN VAN
• Application Number:
  US12/638,318
• Publication Number:
  US 20100094211A1
• Time in Patent Office: 875 Days
• Field of Search: 606/108, 606/159, 606/170, 606/191, 606/192, 606/194, 604/103.04, 604/96, 604/102.02, 604/523, 604/524
• US Class Current: 606/159
• CPC Class Codes: A61B 17/320725 with radially expandable cutting or abrading elements A61B17/32075 takes precedence
• CPC Class Codes: A61B 2017/22061 for spreading elements apart
• CPC Class Codes: A61M 2025/0063 having means, e.g. stylets, mandrils, rods or wires to reinforce or adjust temporarily the stiffness, column strength or pushability of catheters which are already inserted into the human body
• CPC Class Codes: A61M 2025/0183 Rapid exchange or monorail catheters
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility

Abstract

Rapid exchange angioplasty catheters and methods of constructing rapid exchange angioplasty catheters including features that provide good pushability and kink resistance. In an illustrative embodiment, a catheter is provided, the illustrative catheter including a proximal hypotube section, which connects to a more distal braided catheter section. The braided catheter section connects to a midshaft portion that includes a guidewire entry port. Distal of the midshaft portion is a distal section having a balloon disposed thereon. An inflation lumen extends the length of the catheter, while a guidewire lumen extends only from the guidewire entry port to the distal end of the catheter. Optionally, a core wire may extend across the joint from the hypotube, to the braided catheter section, and past the guidewire entry port.

Claims

1. A rapid exchange catheter comprising:

an elongated shaft having a proximal end and a distal end, the elongated shaft including;

a hypotube having a proximal end and a distal end;

a first midshaft portion including a braided member having a proximal end and a distal end, the first midshaft portion being attached near its proximal end to a location near the distal end of the hypotube;

a second midshaft portion having a proximal end, a distal end, and a guidewire entry port, the second midshaft portion being attached near its proximal end to a location near the distal end of the first midshaft portion;

wherein the first midshaft portion includes a flared portion and a tab prior to being attached to the second midshaft portion such that when the first midshaft portion and the second midshaft portion are attached, the tab is disposed within a lumen of the second midshaft portion, a first portion of the braided member is disposed radially exterior to an outer surface of the second midshaft portion, and a second portion of the braided member is disposed within the lumen of the second midshaft portion along an interface between the first midshaft portion and the second midshaft portion in which the first midshaft portion overlaps the second midshaft portion; and

a distal portion defining a short guidewire lumen and an inflation lumen, the distal portion being attached to the second midshaft portion and extending distally therefrom;

a balloon disposed near the distal end of the elongated shaft; and

a core wire attached to the hypotube and extending distally of the distal end of the hypotube and across the location at which the proximal end of the first midshaft portion is attached to the distal end of the hypotube.

2. The rapid exchange catheter of claim 1, wherein the core wire is tapered.

3. The rapid exchange catheter of claim 2, wherein the core wire extends distally beyond the guidewire entry port.

4. The rapid exchange catheter of claim 2, wherein the core wire extends past the proximal end of the guide wire lumen.

5. The rapid exchange catheter of claim 1, wherein the first midshaft portion includes a lubricious inner layer, a braid disposed about the lubricious inner layer, and a polymeric outer layer placed over the braid.

6. The rapid exchange catheter of claim 5, wherein the outer layer is comprised of a polyether block amide.

7. The rapid exchange catheter of claim 5 wherein the first midshaft portion further includes a hydrophilic coating disposed on the outside of the polymeric layer.

8. The rapid exchange catheter of claim 5, wherein the lubricious inner layer includes polyimide.

9. The rapid exchange catheter of claim 5, wherein the braid comprises a number of stainless steel strands.

10. The rapid exchange catheter of claim 1, wherein the first midshaft portion is tapered from its proximal end to its distal end.

11. The rapid exchange catheter of claim 1, wherein the distal end of the hypotube is crimped, and wherein the catheter further comprises a core wire attached to the hypotube, the core wire being placed into the crimp and then secured to the hypotube.

12. The rapid exchange catheter of claim 1, wherein the elongated shaft defines an inflation lumen extending from near the proximal end of the elongated shaft to the balloon and a guidewire lumen extending from the guidewire entry port to the distal end of the elongated shaft.

13. The rapid exchange catheter of claim 1, wherein first midshaft portion includes a polyimide inner layer, a braided steel member disposed about the polyimide inner layer, and a polyether block amide layer disposed about the braided steel member, and a hydrophilic coating disposed on the outside of the polyether block amide layer.

14. The rapid exchange catheter of claim 1, wherein the elongate shaft has an overall length sufficient to reach coronary blood vessels when inserted to a human patient via the femoral artery.

15. The rapid exchange catheter of claim 1, wherein the first midshaft portion is fused to the second midshaft portion using a laser heating process.

16. The rapid exchange catheter of claim 1, further comprising a hub attached adjacent the proximal end of the elongated shaft.

17. A rapid exchange catheter comprising:

an elongated shaft having proximal and distal ends, the elongated shaft including;

a hypotube having a proximal end and a distal end;

a first midshaft member having a braided construction with a proximal end and a distal end, the first midshaft member being attached near its proximal end to a location near the distal end of the hypotube, the first midshaft member including a lubricious inner layer, a braided member disposed about the lubricious inner layer, and a polymeric outer layer placed over the braided member;

a second midshaft portion having a proximal end, a distal end, and a guidewire entry port, the second midshaft portion being attached near its proximal end to a location near the distal end of the first midshaft portion;

wherein the first midshaft portion and the second midshaft portion form a melded structure when attached to one another, and wherein a first portion of the braided member is disposed along and exterior to an outer surface of the second midshaft portion and a second portion of the braided member is disposed within a lumen of the second midshaft portion prior to joining the melded structure;

a distal portion defining a short guidewire lumen and an inflation lumen, the distal portion being attached to the second midshaft portion and extending distally therefrom; and

a tapered core wire attached to the hypotube and extending distally of the distal end of the hypotube, across the location at which the proximal end of the first midshaft portion is attached to the distal end of the hypotube, and past the guidewire entry port; and

a balloon disposed near the distal end of the elongated shaft.

18. The rapid exchange catheter of claim 17, wherein the elongate shaft has an overall length sufficient to reach coronary blood vessels when inserted to a human patient via the femoral artery.

19. The rapid exchange catheter of claim 17, further comprising a hub attached near the proximal end of the elongated shaft.

20. A rapid exchange catheter comprising:

an elongated shaft having proximal and distal ends, the elongated shaft including;

a hypotube having a proximal end and a distal end;

a first midshaft member having a braided construction with a proximal end and a distal end, the first midshaft member being attached near its proximal end to a location near the distal end of the hypotube, the first midshaft member including a lubricious inner layer, a braided member disposed about the lubricious inner layer, and a polymeric outer layer placed over the braided member;

a second midshaft portion having a proximal end, a distal end, and a guidewire entry port, the second midshaft portion being attached near its proximal end to a location near the distal end of the first midshaft portion;

wherein the first midshaft portion and the second midshaft portion form a melded structure when attached to one another, and wherein a first portion of the braided member is disposed along and exterior to an outer surface of the second midshaft portion and a second portion of the braided member is disposed within a lumen of the second midshaft portion prior to joining the melded structure;

a distal portion defining a short guidewire lumen and an inflation lumen, the distal portion being attached to the second midshaft portion and extending distally therefrom; and

a tapered core wire attached to the hypotube and extending distally of the distal end of the hypotube, across the location at which the proximal end of the first midshaft portion is attached to the distal end of the hypotube, and past the guidewire entry port;

a balloon disposed near the distal end of the elongated shaft; and

wherein the lubricious inner layer includes polyimide, the braided member is made of steel, and the polymeric outer layer includes polyether block amide.